The invention relates to a method for producing a sheet-material container for a dispensing unit. The invention also relates to a sheet-material container for a dispensing unit.
Multicomponent compositions, such as mortar, foam and sealing compositions, are made available to the user as multicomponent compositions in cartridges and sheet-material containers. Sheet-material containers usually contain a plurality of sheet-material bags, which are filled with the individual components of the multicomponent composition and are glued into a rigid head part. These have proven successful as packaging for such compositions and are characterized in particular by the small amount of material they contain, which must be discarded after dispensing the composition, in comparison with cartridges. Furthermore, sheet-material containers can be produced easily and inexpensively. A sheet-material container is inserted into a dispensing unit and the components of the composition are forced into outlet channels in the head part with the help of a dispensing mechanism. The individual components of the composition are mixed in a mixer to form the desired composition and then applied to an application site.
The sheet-material bags of the sheet-material container must be opened prior to the initial use. To do so, the user causes the sheet-material bags to rupture with the initial strokes of the dispensing operation. This “passive” opening can be supported by weak spots created in a targeted manner in certain locations on the sheet-material bags or appropriately placed piercing units.
DE 43 35 970 A1 discloses one example of such an opening aid. The end faces of the sheet-material bags are pressed onto spikes by the pressure applied by the dispensing unit so that the blades are oriented across the folds in the sheet-material bags.
A more complicated construction is proposed according to DE 10 2007 018 143 B3. Separate piercing tubes are inserted into the outlet connections of the caps attached to the ends of the sheet-material bags. The piercing tubes may be displaced out of a storage position, in which they are not in contact with the sheet-material bags, into an activation position by attaching a mixer such that in this position the piercing tubes penetrate through the films of the sheet-material bags or at least approximately come in contact with them.
All these approaches have the disadvantage that the outlet channels in the head part are not filled with the components of the composition prior to the initial use. This means that the user must first fill up the empty volume in the head part before the components of the composition will exit into the mixer. To synchronize the throughputs of the components of the composition in the case of multicomponent systems, the user is also required to perform a certain number of strokes before the actual application and to discard the quantities thereby conveyed.
Except for a deviation from the desired mixing ratio in the case of multicomponent systems, the air in the as yet unfilled regions in the head part can have a negative effect on the application or, because of the compressibility of air, there may be an unwanted pressure and flow behavior, which may then lead to disturbances in curing of the multicomponent composition. Another disadvantage of the known approaches with piercing units is the inadequate control over the opening processes. The piercing units do not always ensure satisfactory opening with a sufficiently large opening cross section, even when there has been proper handling by the user. This can also have a negative effect on the quality of the applied composition. In the case of multicomponent systems in particular, an opening that is too small may result in a mixing ratio that cannot be used.
The object of the invention is to create a sheet-material container that will permit immediate satisfactory discharge of the components of the composition when used in a dispensing unit.
The method according to the invention for producing a sheet-material container for a dispensing unit comprises the following steps:
applying a head part to a first end of a sheet-material bag filled with a composition wherein the head part has at least one outlet channel for the composition;
opening the sheet-material bag; and
closing the outlet channel;
wherein the opening of the sheet-material bag and the closing of the outlet channel take place before the initial use of the sheet-material container in the dispensing unit.
The invention is based on the one hand on the finding that the disadvantages described in the introduction can all be overcome if the outlet channels of the head part are completely filled as much as possible with the components of the composition from the beginning. On the other hand, it has been recognized that the sheet-material bag of a sheet-material container need not necessarily be closed before the initial use. According to the invention, the sheet-material bag is intentionally already opened during the method of producing the sheet-material container. This makes it possible for the manufacturer to ensure openings of a sufficiently large size. The opening behavior need no longer be taken into account when selecting films. This yields new freedom in the choice of the packaging.
If a sheet-material bag is opened prematurely, this leads to the problem that the material components may come in contact with air. Furthermore, during storage or shipping of the sheet-material container, unwanted leakage of composition out of the head part is possible. These problems are solved according to the invention by closing the outlet channel already during production of the sheet-material container, i.e., before the initial use of the sheet-material container in the dispensing unit.
On the part of the user, the risks of uncontrolled rupture of the sheet-material bags and soiling are completely suppressed thanks to the present invention. The user need only remove and/or open the closure, for example by unscrewing a cap, and the sheet-material container is ready to use immediately.
The invention thus makes it possible to preserve the advantages offered by the tried and tested technology of filling a sheet-material bag in comparison with the use of hard cartridges and also to transfer certain advantages, which could previously be offered only by hard cartridges that are much more complicated to produce from a technical standpoint, to sheet-material bag systems.
The invention is aimed primarily at multicomponent systems, i.e., at sheet-material containers having a plurality of sheet-material bags, each being filled with one component of a multicomponent composition. However, the invention is fundamentally also applicable for a system having only one sheet-material bag.
According to a preferred embodiment of the production method according to the invention, the sheet-material bag is opened automatically in applying the head part, preferably by a piercing unit provided on the head part. Therefore, production of the sheet-material container is not delayed by the step of opening the sheet-material bag, because this step is performed simultaneously with the application of the head part.
To displace the air in the outlet channel, the outlet channel can be filled with a filling material in the production of the sheet-material container. The filling material can also ensure that the sheet-material bag, after being opened, will not lose too much of its original firm shape, because the component of the composition of the sheet-material bag cannot enter the outlet channel of the head part because of the filling material.
With a suitable choice of the filling material, it can be removed easily before the initial use. An embodiment in which the filling material is connected to a closure part (e.g., a cap) with which the outlet channel is closed is particularly advantageous here. When the closure part is removed by the user, the filling material is then also removed from the outlet channel at the same time.
An alternative embodiment of the production method according to the invention provides that, after opening the sheet-material bag, a portion of the composition is forced as filling material out of the sheet-material bag and into the outlet channel. This means that already in the production of the sheet-material container, the entire cavity of the head part can be filled with the components of the composition in advance, i.e., in preparation for the initial use, which only occurs later so that the user need not be concerned with this task, which is perceived as a nuisance.
According to a particular variant of this embodiment, the sheet-material bag is divided in the production of the sheet-material container, and the open second end of the sheet-material bag, which is formed when the bag is divided, is closed. In doing so, a pressure is applied to the composition in the sheet-material bag by the dividing action or the closing action, such that a portion of the composition is displaced out of the sheet-material bag and into the outlet channel. This variant advantageously allows simultaneous production of two sheet-material containers, starting from an elongated sheet-material bag for each component of the composition, which is initially closed on both ends. A head part is attached to both ends of the sheet-material bag, and the sheet-material bag is opened at both ends. Then the sheet-material bag is divided in the middle as described above, and the newly formed open ends of the two parts are closed. In doing so, the outlet channels are automatically filled with the component of the composition in the case of both sheet-material containers without necessitating any additional finishing step to do so.
Complete filling of the outlet channels according to the above principle can be achieved, for example, by sealing the second end of the sheet-material bag by means of a clip in the standard manner, the width of this clip being selected so that at least a quantity of composition corresponding to the volume of the outlet channel is displaced out of the sheet-material bag and into the outlet channel.
The invention also creates a sheet-material container for a dispensing unit with at least one sheet-material bag, which is filled with a composition, and with a head part, which accommodates one end of the sheet-material bag. The head part has at least one outlet channel for the composition. According to the invention, the sheet-material bag is opened at the first end, and the outlet channel is closed with a closure part, which can be opened or removed by a user.
The sheet-material container according to the invention is characterized in that the sheet-material bag is already opened before the first use, and the composition is prevented from coming in contact with air. Unwanted escape of the composition during storage or shipping of the sheet-material container is prevented by the closure part. With respect to the advantages of the sheet-material container according to the invention in comparison with the prior art, reference is made to the above discussion about the production method according to the invention.
As already explained above, the invention makes it possible to fill the outlet channel of the head part with a filling material, such that the filling material may be the same material as the composition in the sheet-material bag or it may be a different material such as a thermoplastic or elastomer material. In the latter case, the filling material may be attached to the closure part, so that it is automatically extracted from the outlet channel when the closure part is removed.
An attachable or screw-on cap, a valve flap or a seal, e.g., in the form of a welded film, is suitable in particular as the closure part.
With regard to a time-saving assembly of the sheet-material container according to the invention, the head part or the closure part has a piercing unit.
According to an advantageous refinement of this aspect, the piercing unit has an opening tube, which forms a part of the outlet channel for the composition and preferably has a slanted shape and/or sharp edges. The opening tube reliably ensures the creation of a defined opening of a sufficient size in the sheet-material bag.
Additional features and advantages of the invention are derived from the following description and from the accompanying drawings, to which reference is herewith made.